To improve photocatalytic performance, CdS nanoparticle deposited TiO2 nanotubular photocatalysts are synthesized. The TiO2 nanotube is fabricated by electrochemical anodization at a constant voltage of 60 V, and annealed at 500 for crystallization. The CdS nanoparticles on TiO2 nanotubes are synthesized by successive ionic layer adsorption and reaction method. The surface characteristics and photocurrent responses of TNT/CdS photocatalysts are investigated by scanning electron microscopy (SEM), X-ray diffraction (XRD), UV-Vis spectrometer and LED light source installed potentiostat. The bandgaps of the CdS deposited TiO2 photocatalysts are gradually narrowed with increasing of amounts of deposited CdS nanoparticles, which enhances visible light absorption ability of composite photocatalysts. Enhanced photoelectrochemical performance is observed in the nanocomposite TiO2 photocatalyst. However, the maximum photocurrent response and dye degradation efficiency are observed for TNT/CdS30 photocatalyst. The excellent photocatalytic performance of TNT/CdS30 catalyst can be ascribed to the synergistic effects of its better absorption ability of visible light region and efficient charge transport process.

To improve photocatalytic performance, a PbS/ZnO/TiO2 nanotube catalyst was synthesized, and its surface characteristics and photocatalytic efficiency were investigated. The hybrid photocatalysts were produced by anodic oxidation and successive ionic layer adsorption and reaction(SILAR). The photocatalytic efficiency was evaluated using the dye degradation rate. The PbS/ZnO/TiO2 photocatalyst significantly enhanced the photocatalytic activity for dye degradation, which was ascribed to the synergistic effect of their better absorption of solar light and a decrease in the rate of excited electron-hole recombination.

To synthesize a high-performance photocatalyst, N doped TiO2 nanotubes deposited with Ag nanoparticles were synthesized, and surface characteristics, electrochemical behaviors, and photocatalytic activity were investigated. The TiO2 nanotubular photocatalyst was fabricated by anodization; the Ag nanoparticles on the TiO2 nanotubes were synthesized by a reduction reaction in AgNO3 solution under UV irradiation. The XPS results of the N doped TiO2 nanotubes showed that the incorporated nitrogen ions were located in interstitial sites of the TiO2 crystal structure. The N doped titania nanotubes exhibited a high dye degradation rate, which is effectively attributable to the increase of visible light absorption due to interstitial nitrogen ions in the crystalline TiO2 structure. Moreover, the precipitated Ag particles on the titania nanotubes led to a decrease in the rate of electron-hole recombination; the photocurrent of this electrode was higher than that of the pure titania electrode. From electrochemical and dye degradation results, the photocurrent and photocatalytic efficiency were found to have been significantly affected by N doping and the deposition of Ag particles.